Core A Project Summary/Abstract Scientists are generating unique disease models by manipulating single genes and proteins in whole animals, targeted organs and individual cells. Absent at many of the top research institutions are individuals experienced in performing procedures to ascertain the physiological role of these genes and proteins in normal function and disease. This is particularly true in studying the kidney because phenotyping kidney function may require evaluating individual nephron and whole kidney function, and the role the kidney might play in disrupting systemic homeostasis. The overriding goal of the Yale George M. O'Brien Kidney Center Animal Physiology and Phenotyping Core is to provide performance and training services to assist Users phenotype their particular rodent disease model at the systemic, whole kidney and individual nephron segment levels, as appropriate for the model. This breadth of phenotyping services within one Core program facilitates renal research by making it possible for a single animal to be used in more than one phenotyping activity, decreasing the total number of animals need for a thorough phenotyping project. While many of the services offered by the Core were once considered standard laboratory techniques and assays, and were the backbone of the renal labs that originally described normal renal physiology and pathology, there are currently only a small number of institutions with individuals capable of offering this level and breadth of renal function phenotyping. Yet, increasingly, these techniques and assessment approaches are needed to understand whole kidney and nephron function following genetic, experimental and/or environmental manipulations. Thus, the Animal Physiology and Phenotyping Core has three major strengths: 1) the equipment and infrastructure to assist with renal disease model development and provide phenotyping services at the systemic, whole kidney and individual nephron segment level, 2) experienced and skilled personnel capable of generating reliable and reproducible phenotyping data and 3) expertise and experience in designing phenotyping studies and data interpretation. Core staff perform the more difficult phenotyping techniques, e.g., renal clearance studies, kidney perfusion fixation, acute and chronic BP measurements and assaying plasma and urine solute content. For other techniques, e.g., balance, circadian rhythm and activity studies, the Core staff work with Users to ensure the studies are performed correctly, but Users perform the majority of the work. In addition, Core staff assist Users with the proper technique for sample collection, e.g., blood and spot urine collections, and data analysis and interpretation. Thus, by generating data for Users when more specialized or difficult techniques are needed and assisting labs when less difficult techniques are needed, the Animal Physiology and Phenotyping Core can assist the largest number of renal research programs. Core A offers 17 distinct services. During the previous funding period it provided 23,800 services to 59 investigators, which supported studies in >60 manuscripts and 15 funded grant applications.